Grimsby, IL Weather Forecast
Local 7-day forecast
Mostly Sunny then Slight Chance Rain Showers
Track current conditions, temperature changes, wind, and the full daily outlook for Grimsby, IL in one place.
A slight chance of rain showers between 1pm and 4pm. Mostly sunny. High near 98, with temperatures falling to around 96 in the afternoon. Heat index values as high as 106. South southwest wind 1 to 7 mph. Chance of precipitation is 20%.
Local Weather Overview
This forecast page for Grimsby, IL is designed for quick trip planning, giving you a clean read on daytime highs, overnight lows, and changing conditions across the upcoming forecast window. Latest sync: Sep 15, 2026 5:18 PM CDT.
The active forecast window currently covers Sep 16 to Sep 21, 2026 for Grimsby, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Sep 16 to Sep 21, 2026
- Latest sync
- Sep 15, 2026 5:18 PM CDT
- Forecast office
- PAH
- Source
- NOAA / NWS
Daily Outlook
This Week in Grimsby
Thursday looks like the warmest upcoming period in Grimsby at 99 degrees F.
Monday Night is the coolest period ahead with temperatures near 64 degrees F.
The strongest winds are forecast for Saturday at about 2 to 9 mph SSW.
Precipitation is mentioned in 4 upcoming forecast periods.
Forecast Details
- Last updated
- Sep 15, 2026 5:18 PM CDT
- Coverage
- 6 days
- Time zone
- America/Chicago
- Forecast office
- PAH
- Radar station
- KPAH
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Mostly clear, with a low around 73. South wind around 3 mph.
Sunny, with a high near 99. Southwest wind around 5 mph.
Mostly clear, with a low around 72. South southeast wind around 2 mph.
Sunny, with a high near 97. Southwest wind around 2 mph.
Mostly clear, with a low around 72. South southeast wind around 2 mph.
Sunny, with a high near 97. South southwest wind 2 to 9 mph.
Partly cloudy, with a low around 72. South southwest wind 2 to 6 mph.
Mostly sunny, with a high near 95. West southwest wind 2 to 8 mph.
A slight chance of rain showers between 7pm and 1am, then a slight chance of showers and thunderstorms. Partly cloudy, with a low around 68. South southwest wind around 6 mph.
A slight chance of showers and thunderstorms before 1pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 86. Northwest wind 3 to 8 mph.
A chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 64. North wind 2 to 8 mph.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Wednesday
Sep 16
|
Mostly Sunny then Slight Chance Rain Showers
|
98°F |
1 to 7 mph
SSW
|
|
Wednesday Night
Sep 16
|
Mostly Clear
|
73°F |
3 mph
S
|
|
Thursday
Sep 17
|
Sunny
|
99°F |
5 mph
SW
|
|
Thursday Night
Sep 17
|
Mostly Clear
|
72°F |
2 mph
SSE
|
|
Friday
Sep 18
|
Sunny
|
97°F |
2 mph
SW
|
|
Friday Night
Sep 18
|
Mostly Clear
|
72°F |
2 mph
SSE
|
|
Saturday
Sep 19
|
Sunny
|
97°F |
2 to 9 mph
SSW
|
|
Saturday Night
Sep 19
|
Partly Cloudy
|
72°F |
2 to 6 mph
SSW
|
|
Sunday
Sep 20
|
Mostly Sunny
|
95°F |
2 to 8 mph
WSW
|
|
Sunday Night
Sep 20
|
Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms
|
68°F |
6 mph
SSW
|
|
Monday
Sep 21
|
Slight Chance Showers And Thunderstorms
|
86°F |
3 to 8 mph
NW
|
|
Monday Night
Sep 21
|
Chance Showers And Thunderstorms
|
64°F |
2 to 8 mph
N
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Grimsby.